This application is based on and incorporates herein by reference Japanese Patent Application No. 2000-384250 filed on Dec. 18, 2000, and Japanese Patent Application No. 2001-280049 filed on Sep. 14, 2001.
1. Field of the Invention
The present invention relates to fluid machinery that takes in and discharges fluid by reciprocating pistons, and more specifically, to fluid machinery that is applied to a compressor for a vapor compression refrigeration cycle.
2. Description of Related Art
In a compressor disclosed in JP-B No. 4-51667, by revolving a revolution disk around a shaft, pistons reciprocate in a direction orthogonal to a longitudinal direction of the shaft. In the invention disclosed in the above-described publication, because the pistons reciprocate in the direction orthogonal to the longitudinal direction of the shaft, a dimension in a radial direction of the compressor (dimension in a direction orthogonal to the longitudinal direction of the shaft) becomes large. That is, the stroke is large.
In view of the above, the present invention achieves its object of maintaining a smaller dimension in the direction orthogonal to a longitudinal direction of a shaft in a fluid machine that takes in and discharges fluid by reciprocating pistons.
In order to achieve the above-described object, the present invention has a shaft that rotates, a revolving member that revolves by being driven by the shaft, a piston that reciprocates in a direction parallel to a longitudinal direction of the shaft, and a link having one end movably connected to the piston while another end is movably connected to the revolving member. When the revolving member revolves, the piston reciprocates as the link swings with respect to the piston. Alternatively, when motion is transferred to the link from the revolving member when the revolving member revolves, only a radial directional component of the shaft is transferred to the link. Thereby, it is possible to reduce a dimension orthogonal to the longitudinal direction of the shaft.
In another alternative, a connecting portion of the link swings with respect to the revolving member in a plane parallel to a swinging plane of the link with respect to the piston. Thereby, it is possible to reduce a dimension of the direction orthogonal to the longitudinal direction of the shaft. Further yet, a regulating link may be pivotably connected to the revolving member with one end thereof being fixed to the housing so as to swing only in a surface parallel to a swinging surface of the link, while another end thereof is movable with respect to the revolving member in the direction orthogonal to the swinging surface. Thereby, it is possible to reduce a dimension of the direction orthogonal to the longitudinal direction of the shaft. Moreover, with the regulating link, it is possible to easily prevent the revolving member from rotating.
Continuing with alternate embodiments, there may be a linkage constituted of a first and second link rotatably connected to each other. One end of the first link is swingably connected to the piston and another end thereof is rotatably connected to a connecting portion provided on one end of the second link. Another end of the second link has a swing center fixed to the housing so that the second link can swing in a surface parallel to a swinging surface of the first link with respect to the piston. The second link is also swingably connected to the revolving member with a portion between the swing center and the connecting portion of the second link being movable in a direction orthogonal to the swinging surface. Accordingly, it is possible to reduce a dimension of the direction orthogonal to the longitudinal direction of the shaft.
The present invention may also be constructed so that the link swings with respect to the piston so that a connecting position of the link with the revolving member passes through a center of the piston and reciprocates on both sides of the piston with regard to the piston axial line (Lp) parallel to the longitudinal direction of the shaft. Accordingly, it becomes possible to have the piston reciprocate twice as the shaft rotates once. Thus, for example, in comparison to a swash plate type or a waffle-type compressor whose piston reciprocates once while the shaft thereof makes one rotation, it is possible to obtain an equal discharge amount with half the number of cylinders (a number of pistons). Thus, it is possible to reduce a number of pistons and parts related thereto, thus allowing for a lighter fluid machine as well as reducing manufacturing costs thereof.
Furthermore, the introduction of a rotation prevention mechanism (R) for preventing the revolving member from rotating with respect to the housings comprises a piston that reciprocates in a direction parallel to the longitudinal direction of the shaft, and a link having one end movably connected to the piston while another end is movably connected to the revolving member. The device further requires that when the revolving member revolves, the piston reciprocates by the link swinging with respect to the piston. Accordingly, it is possible to prevent the revolving member from revolving by the rotation prevention mechanism (R), and at the same time, to have the piston reciprocate in the direction parallel to the longitudinal direction of the shaft, and thus, it is possible to downsize a dimension of the direction orthogonal to the longitudinal direction of the shaft.
Additionally, by providing a balancer controlling means for changing an inertial moment of the balancer by interlocking with the operation of a stroke controlling means, it is possible to prevent an amplitude of the fluid machinery from increasing even when the discharge volume is variably controlled. In this case, it is desirable to change the inertial moment of the balancer by displacing a position of a gravity point of a plurality of weights with respect to the shaft.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.